Takao Shimayoshi

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In our companion paper, the physiological functions of pancreatic β cells were analyzed with a new β-cell model by time-based integration of a set of differential equations that describe individual reaction steps or functional components based on experimental studies. In this study, we calculate steady-state solutions of these differential equations to(More)
The action potential, once triggered in ventricular or atrial myocytes, automatically proceeds on its time course or is generated spontaneously in sinoatrial node pacemaker cells. It is induced by complex interactions among such cellular components as ion channels, transporters, intracellular ion concentrations, and signaling molecules. We have developed(More)
In order to understand the function of biological elements and their interactions, computer analysis and simulation is an essential technique. For higher research efficiency, it is important to provide a system framework for constructing biological simulation systems that handle multiple phenomena. This paper proposes "DynaBioS", a comprehensive system(More)
A stretch-induced increase of active tension is one of the most important properties of the heart, known as the Frank-Starling law. Although a variation of myofilament Ca(2+) sensitivity with sarcomere length (SL) change was found to be involved, the underlying molecular mechanisms are not fully clarified. Some recent experimental studies indicate that a(More)
Multi-scale models of the cardiovascular system provide new insight that was unavailable with in vivo and in vitro experiments. For the cardiovascular system, multi-scale simulations provide a valuable perspective in analyzing the interaction of three phenomenons occurring at different spatial scales: circulatory hemodynamics, ventricular structural(More)
We investigated numerical methods for predictors in a multiscale cardiovascular simulation model. The proposed method predicts initial approximations for the iterative convergence calculations of the strong coupling method using the smoothing spline to remove errors from values of past timesteps and using the linear and second-order extrapolation. The new(More)
It is necessary to use complicated myocardial cell model and heart model to evaluate the regional energy production and consumption which leads to the unrealistic computational time. In this research, a left ventricle (LV) simulation model was constructed which includes accurate myocardial cell model. In order to simulate the model in realistic time, we(More)
The force-velocity (F-V) relationship of filament sliding is traditionally used to define the inotropic condition of striated muscles. A simple circulation model combined with the Laplace heart was developed to get a deeper insight into the relationship between the F-V characteristics and the cardiac ventricular inotropy. The circulation model consists of a(More)
Mathematical cell models are effective tools to understand cellular physiological functions precisely. For detailed analysis of model dynamics in order to investigate how much each component affects cellular behaviour, mathematical approaches are essential. This article presents a numerical analysis technique, which is applicable to any complicated cell(More)
For computer simulations of physiological experiments using physiological models, a machine-readable format of experimental protocols is effective. Here, we propose an XML-based language, PEPML (Physiological Experimental Protocol Markup Language). In the PEPML, conditions and procedures of an experimental protocol are procedurally described as a list of(More)